Hi All,

I am looking for some concrete info on how I can solve the following problem for my project truck..

Currently I have a 1972 GMC Jimmy getting resto-moded. I have installed a 5.3L engine w/trans (4l65e) from a 2004 Chevy Silverado. Unfortunately, the matching ECM and BCU were not available.. So since I was going to install brand new wiring throughout, I bought an ECM off of Ebay with a custom made harness to adapt to the engine and it was from a 99' Camaro. We were able to start the engine and get it running and everything works.

The problem now that I am encountering is that I wanted to use a newer Escalade gauge cluster since they have the Trans Temp gauge already in it. However I was reading in another forum that in order to make it work it has to have the VIN number programmed into it and have the same ECM and BCU that was on the engine.. ??

So my question is... Am I screwed now that I don't have the matching ECU/BCU...? Or is it possible to locate another ECM from another 2004 and simply program it somehow..? I bought the engine so long ago I cannot get the info on it like the VIN for the truck or anything..

Any insight from you wonderful folks would be greatly appreciated..

 

You real should talk with some one like Speartech on how to incorporate everything.

I believe you will need the PCM, the BCM, a cluster, and a dash harness. The PCM and BCM can be re-flashed to all have matching vin's as well as the Cluster. Just realize this is not going to be cheap option.

 

Vin is located on left rear corner on block, take the last 8 numbers to a dealer and you will have the info you need.

 

Wow, really..!! I did not think they had the wherewithal to do that.. I guess I was used to the old style block where they only plated the block# so you could check to see what size it was originally.. Thanks for the valuable info.. I will check that out tomm..

But I guess the issue of non-matching ecm/bcm's is still going to be an issue..

 

The pcm has to be flashed for a truck VIN in order for the pcm to broadcast the trans temp information over the serial data bus. The BCM has no effect on any cluster communications and is used for tow haul activation only and has no bearing on IP cluster operation.

On a basic level assuming the cluster was installed in the truck all it needs is to be hooked into the databus for the fuel gauge, oil pressure, and other serial data controlled features of the cluster to function correctly. BUT, the pcm has to have the oil pressure sender wired, the fuel level sender wired in etc.

At this point since you are building a scratch built vehicle bar none the easiest way to accomplish a working cluster and all related options including tow haul, vehicle lights and small stuff is to grab a complete inside outside wiring harness and install it completely in the donor vehicle. Then it saves the hassle of building and integrating a engine harness into say a painless wiring full vehicle kit etc.

 

Thanks 01WS6/tamu..

However a few more questions. We have looked all over the engine and still cannot locate the VIN info that was mentioned above. Knowing that the PCM has to be flashed with a Vin# in order for the cluster to respond... What other option is there to make this current setup work. I have already spent alot on the truck wiring install and the special harness to be made along with an ECM I cannot now use. ** If I get another PCM from a junkyard from a 2004 silverado truck, What VIN# can be utilized to make it work..? I am asking because I do not know the order or # of steps in which this will take place..

 

whats the service number on the pcm you currently have. Are you goin auto or stick route.

 

Thanks for the quick response.. I was afraid my statement was not making sense.. LOL

I can't get to it until this coming weekend but I will write it down and post it. I started thinking that if I could use the 72's body VIN but then I realized that maybe the PCM would not accept it because it may have less digits than the newer ones.. It will be automatic since I have a 4L65e and a NP208 transfer case..

 

99 computers are kinda limited from what I remember on their internal OS. But the 2001 up 12270411 computer is a direct computer and gives way more programmability to doing a few things. If you can find the newer computer you need to flash it to a 2001 3/4 ton 6.0 with 4L80 auto vin. This will get the pcm broadcasting the trans temp. They then need to do a 4L60E segment swap on the programming side so the transmission will work properly and then they need to program the engine side as per whatever you are putting in the truck.

Then your existing harness needs to have the wiring for the oil pressure gauge ran to the pcm and then the fuel level sender wiring and appropriate sender resistance needs to be retrofitted to your application as necessary for the fuel gauge to work properly.

At that point you need to source a wiring diagram for the instrument cluster of your choosing and wire it up as necessary. You need to stick to the 2000-2002 escalade cluster for the easiest swap as it is less electrically involved than the 2003 up clusters.